It's not unusual to hear someone say, ‘I'd rather be dead than have Alzheimer's’. In ‘Alzheimer Disease (AD) and Preemptive Suicide’,1 Dena Davis explains why this is a reasonable position. People taking this position will welcome the discovery of biomarkers permitting very early AD diagnosis, Davis suggests, for this will enable more of them to end their lives while they remain motivated and able to do so. At the same time, Davis observes, people would have less reason to resort to the drastic remedy of pre-emptive suicide if they had absolute authority over the medical treatment they received as patients with dementia; but the threat of pre-emptive suicide is not, in my view, a sufficient reason to grant competent individuals that authority.

If preclinical diagnosis of AD becomes possible, some pre-emptive suicides will probably occur. There would be no ethical or practical way to ban such suicides, and it would be silly to try. Clinicians will undoubtedly try to discourage people seeking biomarker information in furtherance of a suicide plan, but savvy individuals will simply conceal their true motivation for having the tests. The real problem for people intent on self-destruction is that biomarkers are unlikely to deliver a clear suicide signal.

First, as Davis notes, work on biomarkers remains in the research stage. No one yet knows whether biomarker tests will prove accurate enough to warrant clinical use. Second, even clinically accepted biomarker tests will generate imperfect information about future disease. Biomarkers may produce more accurate estimates of a person's risk of developing AD, but like all predictive tests, they will also yield false positive and negative results. The …